Collet and rod grinder



.OC- 3, 1944- J. TURENCHALK ETAL 2,359,594l

COLLET AND ROD GRINDER- Filed Aug. 30, 1945 @y/mf@ ATTUR NEYB Patented Oct. 3, 1944 UNITED STATES PATENT OFFICE COLLET AND ROD GRIN DER John Turenchalk and Harry Turenchalk, Yonkers, N. Y.

Application August 30, 1943, Serial No. 500,565

9 Claims.

Our invention relates to power operated grinding devices, and has among its objects and advantages the provision of an improved rod grinder mount for stones employed in grinding, drilling, polishing, etc.

Present day stone grinders usually comprise stone heads of various sizes and shapes which are affixed to a metal shaft, the shaft being held in a collet which is driven by a portable rotary tool operated by an electric motor. Such stone heads, because of their small sizes and type of mount, are easily broken. The stones also Wear out in a short time.

Accordingly an object of my invention is to provide a novel collet designed to effectively support rod grinder stones, wherein the construction is such as to handle relatively long stones to increase the wearing life ofthe stones, and in which the collet is capable of supporting short remains of the stones in true concentricity with the axis of the collet.

A further object is to provide a rod stone and collet combination wherein the stone itself may have a length at least equalling that of a conventional stone head and its attached shaft to greatly increase the wearing life of the stone, and in which novel means are provided for imparting radial expansion to the collet to frictionally secure the collet in the tool shaft when the stone has worn down to a relatively short piece.

Another `object is toprovide La collet for supporting a rod stone which may be adjusted axially of the collet to compensate for wear, and in which the collet is of such construction as to effectively hold the stone in true concentricity with its axis regardless of the length of the stone.

A further object is to provide a collet for stones of cylindrical contour wherein the stone may be adjusted axially of the collet to compensate for wear, and in which the collet is of such ccnstruction" as to expand radially at one end to maintain good frictional connection with its rotary drive shaft as the other end of the collet is contracted upon the stone when worn to a relatively short length.

In the accompanying drawing:

Figure 1 is a partial sectional View of the invention in association with j a conventional power operated tool.

Figure 2 is a longitudinal sectional View of the collet taken along the line 2-2 of Figure 1.

Fig. 3 is an end View of the collet.

Figure 4 is a sectional view along the line 4,-?! i of Figure 2.

Figure 5 is a sectional view along the line 5 5 of Figure 2, and

Figure 6 is a view taken from the dicated by line 6-6 of Figure 2.

In the embodiment of the invention selectedA for illustration, Figure 1 illustrates the nose end of a conventional tool I0 of the portable type, which tool is provided with a drive shaft I2 of tubular contour for the reception of one end`of a collet I4. This shaft is threaded for connection with a head nut I6, as at I8. The head nut I6 includes a bore 20 of such diameter as to receive the cylindrical body 22 of the collet. This body is provided with a tapered end face 24 having camming engagement with a correspondingly shaped end face 26in the nut I6 to press the collet upon a tool spindle or other device to be operated by the tool. Such tools include a small electric motor for driving the shaft I2.

The collet I4 is provided with four slots 28 extending. longitudinally thereof and intersecting its .inner end 30. VThese slots are equally spaced one from the other. The collet is also provided With second slots 32 arranged longitudinally of the collet and intersecting its opposite end 34.Y These slots comprise four in number and are equally spaced one from the other but are oiiset 45 degrees from theslots 2B. The slots 32 are of considerable length, extending throughout the greater length of the collet I4 and terminating in a plane transversely of the axis of the collet slightly short of the similar plane of the slots 28. Thus the collet I4 includes four` short fingers 36 and four long ngers 38. The lingers 38 may be position inconstricted upon tools inserted in the collet through rotation of the head nut I6 to bring the face 26 into camming engagement with the face Conventional collets have a length usually terminating at the outer end of the fa-ce 24. In the instant case, the collet is of greater length, and the lingers 38 are provided with tapered' external threads 40 for threaded connection with a collar 42 having tapered internal threads 44' for coaction withthe threads 40 to press the fingers 38 upon the work.

In Figure 1, a grinding stone 46 is mounted in the collet I4, which grinding stone is of cylindrical contour. This stone has an original length exceeding that of the collet I4, with the stone originally adjusted as to project whatever operating. length is required. Such a stone isV characterized by a long wearing life and the stonev`r the work, and means for flexing uponthe tool.

46 is of considerable length, the stone may be effectively secured inY the collet through tightening of the head nut I6. v

VWhen the stone 46 becomes worn to a short i length, the stone is effectively supported in the collet by reason of the collar 42. 'I'his collar is provided with openings 48 for coaction with a Spanner wrench, through the medium of which the collar may be tightened onV the threaded iingers 38. Upon tightening of the collarY 42, particularly when the stone 46 is of a short length, the fingers 38 are 46, while the `fingers 36 are caused to expand into firm frictional engagement with thel shaft I2.

Such relative movement of the fingers 36 and*Y w,- 38 is permitted by reason of the arrangement' ofi the slots 28 and 32, this arrangement being such that the unslotted material in the zone of the collet adjacent the two sets of slots functions as a fulcrum which flexes to permit radial expanas are used. at the present time.

stones wear down in arrelatively short period of time, and the heads are. weakenedv Iby reason of their connection with the spindle; In the'present case the stone 46 is of such original length as to provide a grinding elementwhich will outwear many grinders of, the head and spindle type. InY addition, the stone i's uninipaired by @spindle attaching formations and devices; I

Without ,further elaboration, theY foregoing will so full-y explainour invention, that others may, by applying', current knowledge, readily adapt the same for use under various conditionsv of service. Y

1 We claim:

11. In combination with a. power driven element having a bore, a collet having an end receivable insaid bore, a cylindricalY stone receivable insaid', collet, said collet having first fingers fitting insaid bore. and second fingers fitting over said stone, and means for pressing said second ngers upon the stone and radially expanding the firstngers against the face of said bore.

2.` In combination with a power driven Velement having an opening, a work supportingI collet, said collet having first fingers receivable in said opening and second fingers to extend over the' collet to radially expand the first fingers against the face of said opening and to press the second fingers 3.. In a tool of the type described having a power driven element of socket likecontour, a collet comprising ,a tubular, member slotted inwardly of one end to provide' first fingersA receivable in saidsocket like element, said collet being slotted inwardly from its otherv end to provide second work gripping fingers, the ,slots in the respective ends of the collet terminating in a manner providing an unslotted: annular bodyA pressed firmly upon the stone' l stone eliminates theV combination stoneheads and spindles such Conventional` comprising a fulcrum for the first and second fingers, and means for clamping the second fingers upon work positioned therebetween and to impart radial expansion to the first fingers through flexing of the collet in the zone of said fulcrum.

4. In combination with a power driven element having a bore, a collet having an end receivable in said bore, a cylindrical stone receivable in said collet, said collet having first fingers fitting in said bore and second Vfingers fitting over said stone, and means for pressing said second fingers upon the stone and radially expanding the'rst ngers against the face of said bore, said means comprising a tapered formation on said collet and a second tapered formation engaging the rst tapered formation to press the first fingers upon the stone through relative movement of the tapered faces.

5. In a tool of the type described having a power driven element of socket like contour, a collet comprising a tubular member slotted inwardly of one end to provide` first fingers .receivable in said socket like element, said collet being slotted inwardly from its other end to provide second work gripping fingers, the slotsI in the respective ends ofthe collet terminating in a manner providing anr unslotted' annular body comprising a fulcrumfor the first andI second. fingers, and means for clamping the second 1in-l gers upon Work positioned' therebetween and tof impart radial expansion to" the first fingers through flexing of the fulcrum, said means comprising al headf nut threadedly connectedy with said element and' coacting cam faces onrthe head nut and the collet.

6. The inventionrdescribed in claim Vl wherein:

said first fingers ,are ciset with respect: t0 the:

second fingers circumferentially of the collet.y

7. A- collet of. thefty-pe describedY comprising a` sleeve like body slotted inwardly of each end to provide first and second fingers, said body being unslotted throughout a short; lengthv between the two sets of slots ton provide afulcrum about which` Vthe divided parts of4 the collar may pivot.

8. In combination with av power driven Yelement having a socket, a collet having an end,

receivable in said socket, cam faces on said collet, a head. nut threadedly connected vwith saidA element and. having. ay cam face engageable. with: said rst cam faces to. press the collet upon a tool. inserted therein, said collet havingan extension beyond. said cam faces, saidV extension having tapered threads, and a'` collar having tapered threads coacting with said rstmentioned tapered threads to press the collet upon the. tool.

9. In combination withY a power drivenelement having a bore, a collet having an end receivable in said bore, a stone receivable in said collet, said collet having relatively stiff, short fingers fitting in said bore and second relatively long, more flexible fingers fitting over said stone, means for pressing said second fingers upon the stone and radially expanding they first ngers against the face of a said bore, including tapered exterior threads on said second Vmore fiexible fingers, and a collar having tapered internal thread coasting with said external threads to constrict the second fingers upon said stone.

JOHN TURENCHALK. :HARRYl TURENCHAIK;

collet in the zoneof, said 

